What is the main purpose of the OpenID protocol in an authentication system?

The main purpose of the OpenID protocol is to provide users with a single sign-on experience across multiple websites and applications using one account. OpenID allows services to delegate the authentication process to a trusted provider (such as Google or Facebook), simplifying login and increasing security.

The protocol transmits user identification information from the provider to the application, allowing the latter to verify identity without storing passwords.

Thus, OpenID facilitates account management and reduces risks associated with password storage and handling.